AU2009324267B2

AU2009324267B2 - Coupler draft gear

Info

Publication number: AU2009324267B2
Application number: AU2009324267A
Authority: AU
Inventors: Long Chen; Shengguo Cong; Yingjun Cui; Yan Jiang; Qingmin Meng; Junlong Wang; Xiaolong Wang
Original assignee: CRRC Qiqihar Rolling Stock Co Ltd; CRRC Mudanjiang Jinyuan Casting Co Ltd
Current assignee: CRRC Qiqihar Rolling Stock Co Ltd; CRRC Mudanjiang Jinyuan Casting Co Ltd
Priority date: 2009-01-23
Filing date: 2009-07-24
Publication date: 2012-04-26
Anticipated expiration: 2029-07-24
Also published as: WO2010083676A1; AU2009324267A1; CN101475012A; CN101475012B

Abstract

uninaien rei.: uriuuY-uvs-uvYqAu PCTOriginal A coupler includes a coupler head, a coupler shank and a coupler tail. The middle portion of a coupler tail end surface of the coupler tail is a cylindrical surface, and two shoulders are symmetrically disposed at both sides of the cylindrical surface, respectively. The present invention further provides a follower plate. The middle portion of a bearing surface of the follower plate is a cylindrical surface, two shoulders are symmetrically disposed at both sides of the cylindrical surface, respectively. The engagement portion between the tail of the coupler and the follower plate is a structure including a cylindrical surface and two symmetrical shoulders, which may enhance the automatic centring ability of the coupler and improve the dynamic stability of the locomotive or car. The present invention also provides a coupler draft gear including a coupler yoke frame, a draft key and the above follower plate.

Description

COUPLER DRAFT GEAR 10001] The present application claims benefit of the priority to CN application No. 200910008461.2 titled "COUPLER, FOLLOWER PLATE AND COUPLER DRAFT GEAR", filed with the Chinese State Intellectual Property Office on January 23, 2009. The entire disclosures thereof are incorporated herein by reference. FIELD OF THE INVENTION 100021 The present invention relates to a traction device for railcar, and specifically to a coupler draft gear. DESCRIPTION OF THE RELATED ART 100031 The coupler draft gear is an important component of railcar, and located at both ends of a locomotive or car. The coupler draft gear is used to achieve the coupling between locomotives or cars, transmit a traction force or compression force, and cushion a longitudinal impact. The coupler draft gear mainly consists of a coupler, a buffer, a coupler yoke frame, a follower plate and a draft key, and is a key component to ensure the transportation safety in railroad. 100041 Please refer to Figs. I and 2, in which Fig. 1 is a schematic structural view of conventional coupler draft gear; and Fig. 2 is a top view of Fig. 1. This coupler draft gear is applied in SS4G type and HXD1 type freight electric locomotive with 8 axes of load-carrying train on Da-Qin line. The configuration and the operation of the coupler draft gear are as follows. A follower plate 3 and a buffer 4 are installed in a coupler yoke frame 5. A coupler 1 is connected to the coupler yoke frame 5 through a draft key 2. When the locomotive or car is drawn, the coupler I is pulled and then drives the coupler yoke frame 5 and a rear follower plate (not shown) to move forwardly through the draft key 2. The traction force is transmitted to the front follower plate 3 via the buffer 4. At this moment, the front follower plate 3 is stopped by a front follower plate seat 6 and cannot move. The applied force is sequentially transmitted from the coupler 1, the coupler yoke frame 5, the buffer 4, the follower plate 3, the front follower plate seat 6 to a traction beam (not shown). When the locomotive or car is subject to impact, the coupler I is pressed, and then drives the coupler yoke frame 5 and the front follower plate 3 to move Doc ID 13872548 1 backwardly. The impact force is transmitted to the rear follower plate via the buffer 4. At this moment, the rear follower plate is stopped by a rear follower plate seat 7 and cannot move. The applied force is sequentially transmitted from the coupler 1, the follower plate 3, the buffer 4, the rear follower plate seat 7 to the traction beam. In both conditions, the buffer 4 may be compressed, and performs the functions of absorbing energy and cushioning the longitudinal impact and transmitting the impact force or traction force to the traction beam. The above-described coupler draft gear may achieve the coupling between two cars, and reliably transmit a longitudinal force. However, the coupler 1 has a poor automatic centreing ability, which will be further described. 100051 Please refer to Figs. 3 to 8, in which Fig. 3 is a schematic structural view of the coupler in Fig. 1; Fig. 4 is a top view of Fig. 3; Fig. 5 is a schematic structural view of the follower plate in Fig. 1; Fig. 6 is a top view of Fig. 5; Fig. 7 is a schematic structural view of the coupler yoke frame in Fig. 1; and Fig. 8 is a top view of Fig. 7. The coupler 1 consists of a coupler head 11, a coupler shank 12 and a coupler tail 13. The coupler tail 13 is provided with a coupler pin hole 131, and the end surface 132 of the coupler tail is a cylindrical surface. The follower plate 3 includes a follower plate body 31 and a bearing body 32, and the bearing surface 321 of the bearing body 32 is a cylindrical surface. A yoke frame inner cavity 51 is provided in the head of the coupler yoke frame 5 to receive the coupler tail 13 of the coupler 1. A coupler yoke frame pin hole 52 is further provided in the head of the coupler yoke frame 5 to receive the draft key 2 which connects the coupler 1 and the coupler yoke frame 5. 100061 Please also refer to Figs. 1 and 2, in the case of running of car, the coupler 1 may be deflected, and the angle deflecting from the center line of the car body is depended on the transverse dimension of the coupler yoke frame inner cavity 51 and the size of the coupler yoke frame pin hole 52 (the largest horizontal deflection angle of this type coupler I is ±70). In particular, since the end surface 132 of the coupler tail and the bearing surface 321 of the follower plate are both cylindrical surfaces, the engagement therebetween allow the coupler 1 to have automatic centreing ability, but the automatic centreing ability thereof is limited, which will be further analyzed. (00071 Please refer to Fig. 9, which is a schematic view showing the force applied to the coupler in Fig. 1 in deflected state. Suppose that the force applied to the coupler head is Fl and the force applied to the coupler tail is F2, in the case that the end surface 132 of the coupler tail and the Doc ID 13872548 2 bearing surface 321 of the follower plate are cylindrical surfaces, the directions of the force Fl applied to the coupler head and the force F2 applied to the coupler tail are opposite with each other, so that the longitudinal force of the locomotive or car is transmitted along the longitudinal centre line AA' of the coupler. When the coupler I is reflected by angle a relative to the centre line CC' of car body, the angle P between the action line BB' of the longitudinal force and the centre line CC' of the car body equals to a, so that a transverse component force is generated from the longitudinal force, which will directly affect the dynamic stability of the locomotive or car and even cause derail accident if the transverse component force is large enough. [00081 In addition, the above coupler also has the following disadvantages. On the one hand, the coupler lacks an anti-disengaging function, i.e., the function of preventing two couplers from disengaging due to excessive height difference between the couplers, which may cause separation accident of train. On the other hand, the anti-creep performance of the coupler is poor, that is, the poor performance of preventing the coupler from spontaneously unlocking because the coupler knuckle lock and the upper (lower) lockpin bounces due to the vibration. 100091 Reference to any prior art in the specification is not, and should not be taken as, an acknowledgment or any form of suggestion that this prior art forms part of the common general knowledge in Australia or any other jurisdiction or that this prior art could reasonably be expected to be ascertained, understood and regarded as relevant by a person skilled in the art. SUMMARY OF THE INVENTION 100101 In view of this, the present invention provides a novel coupler draft gear. [00111 In a first aspect, the present invention provides a coupler draft gear including: a coupler including a coupler head, a coupler shank and a coupler tail, wherein the middle portion of the coupler tail end surface of the coupler tail is a cylindrical surface, two shoulders are symmetrically disposed at both sides of the cylindrical surface respectively, and the coupler tail of the coupler is provided with a coupler pin hole; a coupler yoke frame, wherein a coupler yoke frame inner cavity is provided in a head of the coupler yoke frame to receive the coupler tail of the coupler, and the head of the coupler yoke frame is provided with a coupler yoke frame pin hole; a draft key, which can be inserted in the coupler pin hole and the coupler yoke frame pin hole Doc ID 13872548 3 to connect the coupler and the coupler yoke frame; and a follower plate, wherein a middle portion of a bearing surface of the follower plate is a cylindrical surface, two shoulders are symmetrically disposed at both sides of the cylindrical surface, respectively; and an automatic centreing of the coupler is achieved by engagements between the cylindrical surface, shoulders of the bearing surface of the follower plate and the cylindrical surface, coupler tail shoulders of the coupler tail of the coupler, respectively. 100121 In the above coupler draft gear, a width of the head of the coupler yoke frame is approximately equal to the distance between the opposite inner surfaces of the two front follower plate seat inner stops. 100131 Preferably, the coupler head includes a coupler knuckle, a coupler knuckle pin, a knuckle thrower, a coupler knuckle lock, a lower lockpin assembly and a lower lockpin rotation shaft. When the lower lockpin rotation shaft is rotated, the lower lockpin assembly actuates such that the coupler knuckle lock moves up and down in an inner cavity of a coupler head of the coupler to drive a pushing foot of the knuckle thrower to rotate and push the coupler knuckle to rotate around the coupler knuckle pin. 100141 Preferably, an lower lockpin rod anti-creep bulge is provided at a top of the connection portion of the lower lockpin rod connecting with the lower lockpin rotation shaft, a coupler head inner cavity anti-creep surface is provided at a lower portion of the inner cavity of the coupler head of the coupler, and the lower lockpin rod anti-creep bulge and the coupler head inner cavity anti-creep surface are configured to stop the lower lockpin rod from rotating in an unlocking direction. 100151 Preferably, a seat lock table for bearing the coupler knuckle lock is provided in the coupler knuckle; a lower lockpin anti-creep surface is provided at a top portion of the lower lockpin, and the lower lockpin is stopped from moving upwardly in the unlocking direction by the engagement between the lower lockpin anti-creep surface and a bottom surface of the seat lock table. 100161 Preferably, the coupler further includes an anti-creep bolt. The lower lockpin rod is stopped from entering into the inner cavity of the coupler head of the coupler by inserting anti-creep bolt into a locked indicator hole of the lower lockpin rod. [00171 Preferably, a transverse dimension of the inner cavity of the head of the coupler yoke Doc ID 13872548 4 frame is 70-80% of a width of the head of the coupler yoke frame; and a transverse angle of the coupler yoke frame pin hole is 220. 100181 Preferably, a bearing surface of a tail of the coupler yoke frame is a planar surface, and four corners thereof are connected to buffer grooves via filleted transition structure. 10019] Preferably, the draft key is a flat pin. 100201 Compared with the prior art, the present invention has the following advantages: (1) The coupler has a strong automatic centreing ability. When the coupler is deflected and the coupler tail shoulder contacts with the follower plate shoulder, the two centreing shoulders play the role of centreing. At this moment, the transmission direction of longitudinal force applied to the coupler is changed, and the transverse component force of the longitudinal force is relatively decreased, thereby minimizing the influence on the dynamic stability of the locomotive or car. (2) The coupler has an anti-disengaging tab structure. It may efficiently prevent the separation and collision accident between cars from happening due to the disengagement of two coupled couplers, and avoid the train derail accident caused by the fracture of the coupler shank, the coupler knuckle and the coupler yoke frame of the coupler, which minimizes the potential safety hazard to train due to the fracture of the coupler shank, the coupler knuckle and the coupler yoke frame. Therefore, the transportation safety is improved. (3) The coupler has anti-creep function performed by a lower lockpin and lower lockpin rod. The anti-creep bolt is installed in the locked indicator hole of the lower lockpin rod of the coupler. The lower lockpin, the lower lockpin rod and the anti-creep bolt may efficiently prevent the coupler from being accidentally unlocked during the car is running. Therefore, the coupling reliability between couplers is further improved. [0021] As used herein, except where the context requires otherwise, the term "comprise" and variations of the term, such as "comprising", "comprises" and "comprised", are not intended to exclude further additives, components, integers or steps. 10022] Further aspects of the present invention and further embodiments of the aspects described in the preceding paragraphs will become apparent from the following description, given by way of example and with reference to the accompanying drawings. Doc ID 13872548 5 BRIEF DESCRIPTION of the DRAWINGS 10023] Figure 1 is a schematic structural view of conventional coupler draft gear; 100241 Figure 2 is a top view of Fig. 1; 100251 Figure 3 is a schematic structural view of the coupler in Fig. 1; 100261 Figure 4 is a top view of Fig. 3; [0027] Figure 5 is a schematic structural view of the follower plate in Fig. 1; 100281 Figure 6 is a top view of Fig. 5; 100291 Figure 7 is a schematic structural view of the coupler yoke frame in Fig. 1; 100301 Figure 8 is a top view of Fig. 7; 10031] Figure 9 is a schematic view showing the force applied to the coupler in Fig. I in deflected state; 100321 Figure 10 is a schematic structural view of the coupler of an embodiment of the present invention; [00331 Figure I I is a top view of Fig. 10; 100341 Figure 12 is a partial sectional view of the coupler in Fig. 10 being in the locked state; [0035] Figure 13 is a partial sectional view of the coupler in Fig. 10 being in the unlock state; (0036] Figure 14 is a partial sectional view of the coupler in Fig. 10 being in the full open state; [0037] Figure 15 is a schematic structural view of the follower plate of an embodiment of the present invention; [00381 Figure 16 is a top view of Fig. 15; [0039] Figure 17 is a schematic structural view of the coupler draft gear of an embodiment of the present invention; 100401 Figure 18 is a top view of Fig. 17; [0041] Figure 19 is a schematic view showing the force applied to the coupler of an embodiment Doc ID 13872548 6 of the present invention in deflected state; 100421 Figure 20 is a schematic structural view of the coupler yoke frame in Fig. 17; 100431 Figure 21 is a top view of Fig. 20; 100441 Figure 22 is a schematic partial view of the coupler draft gear shown in Fig. 18; 100451 Figure 23 is a schematic view showing the anti-creep function performed by the lower lockpin rod of the coupler shank of an embodiment of the present invention (not in the anti-creep position); 100461 Figure 24 is a schematic view showing the anti-creep function performed by the lower lockpin rod of the coupler shank of an embodiment of the present invention (in the anti-creep position); [00471 Figure 25 is a schematic view showing the anti-creep function performed by the lower lockpin of the coupler shank of an embodiment of the present invention (side view); and 100481 Figure 26 is a schematic view showing the anti-creep function performed by the lower lockpin of the coupler shank of an embodiment of the present invention (top view). DETAILED DESCRIPTION [00491 In the present disclosure, the end surface of the tail of the coupler is designed as a structure including a cylindrical surface and two symmetric shoulders, and the follower plate is accordingly designed as a structure including a cylindrical surface and two symmetric shoulders, so as to improve the automatic centreing ability of the coupler. [00501 Hereinafter, the present invention will be described in detail by way of embodiments with referring to figures. 100511 Please refer to Figs. 10 and 11, in which Fig. 10 is a schematic structural view of the coupler of an embodiment of the present invention and Fig. 11 a top view of Fig. 10. In the coupler 1, the coupler head 11 includes a coupler knuckle 111, a coupler knuckle pin 115, a knuckle thrower 117, a coupler knuckle lock 116, a lower lockpin assembly (including a lower lockpin and a lower lockpin rod 113) and a lower lockpin rotation shaft 119. When the lower lockpin rotation shaft 119 is rotated, the lower lockpin assembly is actuated such that the coupler knuckle lock 116 moves up and down in the inner cavity of the coupler head of the coupler and Doc ID 13872548 7 drives the pushing foot of the knuckle thrower 117 to rotate, and then pushes the coupler knuckle 111 to rotate around the coupler knuckle pin 115. A coupler pin hole 131 is provided in the coupler tail 13 of the coupler. A coupler tail cylindrical surface 1321 is disposed at the middle portion of the coupler tail end surface 132, and two coupler tail shoulders 1322 are symmetrically disposes at both sides of the coupler tail cylindrical surface 1321, respectively. [00521 The structure and the operating principle of the above coupler head are basically same as that of 17 type coupler. The knuckle thrower 117 is disposed in the inner cavity of the coupler head of the coupler, and may push the coupler knuckle I11 to rotate around the coupler knuckle pin 115. The lock shaft of the lower lockpin is connected with the lock leg of the coupler knuckle lock 116, and the other end of the lower lockpin is connected with the lower lockpin rod 113. The other end of the lower lockpin rod 113 is connected to a coupler lifting bar (not shown) through the lower lockpin rotation shaft 119. Under the effect of the coupler lifting bar, the lower lockpin assembly is rotated around the lower lockpin rotation shaft 119, and further drives the coupler knuckle lock 116 to move. The detailed operating process thereof is the same as that of 17 type coupler, and thus is omitted therein. 100531 Similarly, the coupler I of the present invention may be also operated in three states, i.e., locked state, unlock state and full open state, which will be briefly described. [00541 Please refer to Fig. 12, which is a partial sectional view of the coupler in Fig. 10 being in the locked state. When the coupler knuckle 111 is in the locked position, the coupler knuckle lock is seated on a seat lock table of the tail of the coupler knuckle 111, and the coupler knuckle I 11 cannot rotate around the coupler knuckle pin 115, which is the locked position. [00551 Please refer to Fig. 13, which is a partial sectional view of the coupler in Fig. 10 being in the unlock state. After a coupler lifting bar (not shown) is manipulated, the lower lockpin rotation shaft 119 drives the lower lockpin rod 113 and the lower lockpin 112 to rotate, and the coupler knuckle lock 116 is lifted up to a certain height. Then, the coupler lifting bar is put down, and the coupler knuckle lock 116 is positioned on a seat lock surface of the knuckle thrower 117. At this moment, the coupler knuckle 111 cannot be spontaneously opened. However, if the coupler is subject to a traction force, the coupler knuckle Il l may rotate around the coupler knuckle pin 115, which is the unlock position. 10056] Please refer to Fig. 14, which is a partial sectional view of the coupler in Fig. 10 being in Doc ID 13872548 8 the full open state. The coupler lifting bar is continued to be manipulated, so that the coupler knuckle lock 116 is lifted up to the limit height. At this moment, the coupler knuckle 111 may rotate around the coupler knuckle pin 115 to open, which is the full open position. 100571 A coupler tail cylindrical surface 1321 is disposed at the middle portion of the coupler tail end surface 132, and two coupler tail shoulders 1322 are symmetrically disposed at both sides of the coupler tail cylindrical surface 1321, respectively, which facilitates improving the automatic centreing ability of the coupler 1. Of cause, some components, such as follower plate 3 and coupler yoke frame 5, need to be improved, which will be described as follows. 100581 Please refer to Figs. 15 and 16, in which Fig. 15 a schematic structural view of the follower plate of an embodiment of the present invention and Fig. 16 is a top view of Fig. 15. The follower plate 3 includes a follower plate body 31 and a bearing body 32. A follower plate cylindrical surface 3211 is disposed at the middle portion of the follower plate bearing surface 321, and two follower plate shoulders 3212 are symmetrically disposed at the both sides of the follower plate cylindrical surface 3211, respectively. Similar to 17 type follower plate, the follower plate 3 is made of grade E steel to ensure the structural strength thereof. 10059] Please refer to Figs. 17 to 18, in which Fig. 17 is a schematic structural view of the coupler draft gear of the present invention and Fig. 18 is a top view of Fig. 17. As described above, the end surface of the tail of the coupler I and the bearing surface of the follower plate 3 are accordingly designed as the structure including a cylindrical surface and two symmetrical shoulders. Besides, the dimensions of the follower plate cylindrical surface 3211 and the follower plate shoulder 3212 correspond to the dimensions of the coupler tail cylindrical surface 1321 and the coupler tail shoulder 1322, respectively, so that the automatic centreing ability of the coupler 1 is increased, which will be described hereinafter. 10060] Please refer to Fig. 19, which is a schematic force view showing the force applied to the coupler of an embodiment of the present invention in the deflected state. The automatic centreing ability of the coupler is performed as follows. When the coupler I is deflected, the coupler tail shoulder 1322 contacts with the follower plate bearing surface 321, so that the contact position between the tail of the coupler I and the follower plate 3 is transferred from position A to position B. At this moment, the automatic centreing coupler tail shoulder 1322 functions to change the action spot and transmission direction of longitudinal force. The angle between the action line of longitudinal force and the centre line CC' of car body is relatively decreased, and thus the Doc ID 13872548 9 transverse component force of longitudinal force is decreased, thereby minimizing the influence on the dynamic stability of the locomotive or car. 100611 The free swing angle of the coupler is about 20. That is, when the swing angle is less than 20, the tail of the coupler doesn't contact with the follower plate shoulder 3212, and the coupler may be freely swung. As shown in Fig. 19, when the deflection angle of the coupler 1 is larger than the free swing angle of 20, the automatic centreing shoulder of the tail of the coupler contacts with the follower plate shoulder 3212, and the contact position between the tail of the coupler and the follower plate is transferred from position A to position B. Due to the effect of the automatic centreing shoulder, the action spot and transmission direction of longitudinal force is changed. The angle between the action line BB' of longitudinal force and the centre line AA' of the coupler is y (about 40), and the angle between the action line BB' of the longitudinal force and the centre line CC' of car body is P (about 70 at most). Compared with conventional coupler, the angle between the action line AA' of conventional coupler longitudinal force and the centre line of car body is a (about 110 at most). Therefore, compared with conventional coupler, the angle between the action line of longitudinal force of the coupler I and the centre line CC' of car body is decreased by y (y=a-p=4 0 ), i.e., the automatic centreing ability is 4*. Therefore, the transverse component force of longitudinal force of the coupler in the deflected state is decreased, and the dynamic stability of the locomotive or car is improved. When the reflection angle of the coupler is up to the largest reflection angle 11 , because of the effect of the automatic centreing shoulder, the angle between the action line of longitudinal force and the centre line of car body is decreased from 110 to 70, and thus the transverse component force is decreased by 40%. As the reflection angle of the coupler is decreased, the decreased ratio of the transverse component force is increased. In the above coupler draft gear, in order to meet the automatic centreing ability of the coupler I and the requirement of the transverse reflection angle of the coupler, the coupler yoke frame is required to be accordingly improved, which will be briefly described as follows. 10062] Please refer to Figs. 20 to 22, in which Fig. 20 is a schematic structural view of the coupler yoke frame in Fig. 17; Fig. 21 is a top view of Fig. 20; and Fig. 22 is a schematic partial view of the coupler draft gear shown in Fig. 18. 100631 In the coupler yoke frame 5, the width LI of the head of the coupler yoke frame 5 is increased approximately to the distance between the opposite inner surfaces of the two front follower plate seat inner stops 61 for the follower plate, so that the clearance between the coupler Doc ID 13872548 10 yoke frame 5 and the front follower plate seat inner stops 61 is reduced. Thus, the front follower plate seat inner stops 61 may limit the transverse swing of the coupler yoke frame 5 when the coupler yoke frame 5 is in the traction and compressed states, i.e., the front follower plate seat inner stops 61 perform guiding and positioning functions. [00641 The transverse dimension L2 of the inner cavity 51 of the head of the coupler yoke frame 5 is increased, is approximately equal to 70-80% of the width LI of the head of the coupler yoke frame 5, and is larger than the width of the tail 1322 of the coupler by about 19 mm. The transverse angle 0 of the pin hole 52 of the coupler yoke frame 5 is about 220, so that the horizontal deflection angle of the coupler 1 inside the coupler yoke frame 5 may be increased from ±70 to ±11 0. 100651 As shown in Figs. 20 and 21, the bearing structure of the tail of the coupler yoke frame 5 is shown. The bearing surface 53 of the tail of the coupler yoke frame is a planar surface. The four corners of the tail of the coupler yoke frame 5 and buffer grooves adopt filleted transition structure to improve the applied force state and increase the fatigue resistance at corners of the tail, which is apparently different from conventional coupler yoke frame structure. [0066] As shown in Fig. 22, the draft key 2 is a flat pin, so that the coupler I may be horizontally deflected a corresponding angle to improve the dynamic stability of the coupler draft gear. The transverse angle 0 of the pin hole 52 of the coupler yoke frame has a maximum value of 220, accordingly, the coupler I may be deflected ±1*I relative to the centre line of car body, which facilitates increasing the trafficability of the locomotive or car along curved path. 100671 In particular, the coupler I according to an embodiment has an anti-disengaging function, and relatively strong anti-creep performance, which will be further described as follows. [00681 As shown in Figs. 10 and 11, the coupler head 11 of the coupler 1 is provided with an anti-disengaging tab 114. The top end of the sidewall of the anti-disengaging tab 114 is connected to the lower part of the coupler head, and a bottom wall is transversely protruded from the lower end of the anti-disengaging tab 114 to prevent two coupled couplers from disengaging and separating upwardly and downwardly. 100691 Since the head of the coupler 1 is provided with the anti-disengaging tab 114, it may efficiently prevent two couplers from disengaging due to the excessive height difference between couplers, and prevent the train derail accident caused by the fracture of the coupler shank, the Doc ID 13872548 11 coupler knuckle 111 and the coupler yoke frame 5, which minimizes the potential safety hazard to train due to the fracture of the coupler shank, the coupler knuckle and the coupler yoke frame. Therefore, the transportation safety is improved. 100701 The coupler 1 of an embodiment has triple anti-creep function, i.e., anti-creep performed by the lower lockpin rod, anti-creep performed by the lower lockpin and anti-creep performed by the anti-creep bolt, which will be described as follows. [00711 Please refer to Figs. 23 and 24, in which Fig. 23 is a schematic view showing the anti-creep function performed by the lower lockpin rod of the coupler shank of an embodiment of the present invention (not in the anti-creep position); and Fig. 24 is a schematic view showing the anti-creep function performed by the lower lockpin rod of the coupler shank of an embodiment of the present invention (in the anti-creep position). An anti-creep bulge 1132 is provided at the top portion of the lower lockpin rod 113, and a coupler head inner cavity anti-creep surface 118 is provided at the lower portion of the inner cavity of the coupler head of the coupler. when the car is vibrating, the lower lockpin rod 113 jumps upwardly, so that the anti-creep bulge 1132 of the lower lockpin rod contacts with the anti-creep surface 118 of the inner cavity of the coupler head to restrain the lower lockpin rod 113 from rotating in the unlocking direction and prevent the lower lockpin 112 from further driving the coupler knuckle lock 116 to move upwardly. At this moment, the coupler 1 cannot be unlocked, and is in the locked state. 100721 Please refer to Figs. 25 and 26, in which Fig. 25 is a schematic view showing the anti-creep function performed by the lower lockpin of the coupler shank of an embodiment of the present invention (side view); and Fig. 26 is a schematic view showing the anti-creep function performed by the lower lockpin of the coupler shank of am embodiment of the present invention (top view). A lower lockpin anti-creep surface 1121 is provided at the top portion of the lower lockpin 112, and the coupler knuckle 111 is provided with a seat lock table 1111. when the car is vibrating, the lower lockpin 112 of the coupler jumps upwardly, so that the lower lockpin anti-creep surface 1121 contacts with the bottom surface of the seat lock table 11l of the coupler knuckle to restrain the lower lockpin 112 from continuing to move upwardly, and thus prevent the lower lockpin 112 from further driving the coupler knuckle lock 116 to move upwardly. At this moment, the coupler 1 cannot be unlocked, and is in the locked state. 100731 As shown in Fig. 1, a locked indicator hole 1131 is provided at the middle portion of the lower lockpin rod 113 to indicate whether the coupler 1 is locked in position. The coupler I Doc ID 13872548 12 further includes an anti-creep bolt (not shown), which may be inserted into the locked indicator hole 1131. In use, the anti-creep bolt is inserted into the locked indicator hole 1131 to restrain the lower lockpin rod 113 from entering into the inner cavity of the coupler head of the coupler, and restrain the coupler knuckle lock 116 from moving upwardly and thus preventing the coupler 1 from being unlocked during operation. 100741 Since the coupler 1 has triple anti-creep function, the anti-creep performance thereof is increased. It may efficiently prevent the coupler from being accidentally unlocked when the car is running, and further improve the coupling reliability between couplers. 100751 The coupler 1 of an embodiment of the present invention may achieve automatic centreing function, anti-disengaging function and anti-creep function, without changing the inner structure of the traction beam of conventional locomotive. In addition, the contour and dimension of some components such as the coupler 1, the follower plate 3 and the coupler yoke frame 5 are substantially same as that of a series of 13 type coupler, and the inside components and members adopt that of 17 type coupler, to meet the requirements of consistency and interchangeability with a series of 13 type coupler for conventional SS4G and HXD1 type locomotive. 100761 The preferred embodiments of the present invention have been described. However, it should be noted that the above embodiments should not be deemed as the limit to the present invention. The protection scope of the present invention should be defined by the claims. For persons skilled in the art, many improvements and modifications may also be made to the present invention without departing from the principle of the present invention. The improvements and modifications also fall into the protection scope of the present invention. Doc ID 13872548 13

Claims

1. A coupler draft gear comprising: a coupler comprising a coupler head, a coupler shank and a coupler tail, wherein a middle portion of a coupler tail end surface of the coupler tail is a cylindrical surface, two shoulders are symmetrically disposed at both sides of the cylindrical surface respectively, and the coupler tail of the coupler is provided with a coupler pin hole; a coupler yoke frame, wherein a coupler yoke frame inner cavity is provided in a head of the coupler yoke frame to receive the coupler tail of the coupler, and the head of the coupler yoke frame is provided with a coupler yoke frame pin hole; a draft key, which can be inserted in the coupler pin hole and the coupler yoke frame pin hole to connect the coupler and the coupler yoke frame; and a follower plate, wherein a middle portion of a bearing surface of the follower plate is a cylindrical surface, two shoulders are symmetrically disposed at both sides of the cylindrical surface, respectively; and an automatic centreing of the coupler is achieved by engagements between the cylindrical surface, shoulders of the bearing surface of the follower plate and the cylindrical surface, coupler tail shoulders of the coupler tail of the coupler, respectively, wherein a width of the head of the coupler yoke frame is approximately equal to the distance between the opposite inner surfaces of the two front follower plate seat inner stops.

2. The coupler draft gear according to claim 1, wherein the coupler head comprises a coupler knuckle, a coupler knuckle pin, a knuckle thrower, a coupler knuckle lock, a lower lockpin assembly and a lower lockpin rotation shaft; when the lower lockpin rotation shaft is rotated, the lower lockpin assembly actuates such that the coupler knuckle lock moves up and down in an inner cavity of a coupler head of the coupler to drive a pushing foot of the knuckle thrower to rotate and push the coupler knuckle to rotate around the coupler knuckle pin. Doc ID 13872548 14

3. The coupler draft gear according to claim 2, wherein the coupler head is provided with an anti-disengaging tab; a top end of a sidewall of the anti-disengaging tab is connected to a lower part of the coupler head, and a bottom wall is transversely protruded from a lower end of the anti-disengaging tab to prevent two coupled couplers from disengaging and separating.

4. The coupler draft gear according to claim 2, wherein the lower lockpin assembly comprises a lower lockpin and a lower lockpin rod; a lock shaft of the lower lockpin is connected with a lock leg of the coupler knuckle lock; one end of the lower lockpin rod is connected with the lower lockpin; and the other end of the lower lockpin rod is connected to a coupler lifting bar through the lower lockpin rotation shaft.

5. The coupler draft gear according to claim 4, wherein an lower lockpin rod anti-creep bulge is provided at a top of the connection portion of the lower lockpin rod connecting with the lower lockpin rotation shaft, a coupler head inner cavity anti-creep surface is provided at a lower portion of the inner cavity of the coupler head of the coupler, and the lower lockpin rod anti-creep bulge and the coupler head inner cavity anti-creep surface are configured to stop the lower lockpin rod from rotating in an unlocking direction.

6. The coupler draft gear according to claim 5, wherein a seat lock table for bearing the coupler knuckle lock is provided in the coupler knuckle; a lower lockpin anti-creep surface is provided at a top portion of the lower lockpin, and the lower lockpin is stopped from moving upwardly in the unlocking direction by the engagement between the lower lockpin anti-creep surface and a bottom surface of the seat lock table.

7. The coupler draft gear according to claim 6, wherein the coupler further comprises an anti-creep bolt, the lower lockpin rod is stopped from entering into the inner cavity of the coupler head of the coupler by inserting anti-creep bolt into a locked indicator hole of the lower lockpin rod. Doc ID 13872548 15

8. The coupler draft gear according to any one of claims I to 7, wherein a transverse dimension of the inner cavity of the head of the coupler yoke frame is 70-80% of a width of the head of the coupler yoke frame; and a transverse angle of the coupler yoke frame pin hole is 220.

9. The coupler draft gear according to any one of claims 1 to 8, wherein, a bearing surface of a tail of the coupler yoke frame is a planar surface, and four corners thereof are connected to buffer grooves via filleted transition structure.

10. The coupler draft gear according to any one of claims 1 to 9, wherein the draft key is a flat pin.

11. A coupler draft gear substantially as herein described with reference to Figures 10 to

26. Doc ID 13872548 16